Self-locking bolt



March 21, T` A KlRTON 1,902,454

SELF LOCKING BOLT Filed May 21, 1931 IKL lll/1117.11 I I mfl;

Patented Mar. 21, 1933 i UNITED srh'rss nous A.

rPA'Ilfu ori-"ICBF mil-011, 0l IAMONVILLE, FLORIDA., ASSIGNOR TO Il".,ANTIKE-X131QN' me., or uclxsoxvmn. mama, a coaromrron or noma slm-meme Bom aplauden inea my ai,

This invention relates to attachin ymeans and particularly to bolts adapted to used for holding automobilelicense plates in engagement with supports for the same andthe object of the invention is toprovide'a. bolt so constructed that when the nut has been screwed home and the plates heldin engagement witlreach other, the nut cannot be removed nor the bolt. detached unless the license plate, for instance, is hacked or torn away or unless the bolt is cut 0E.

A further object is to provide a construe'- tion of this character embodying a bolt, a nut therefor, and a washer, the washer and nut being so formed thatV when the bolt is screwed home the nut and washer will be brought into interlocking engagementwith slots in the supporting plate andthe license plate or tag to thus prevent any rotation of the nut or washer, the washer being further so formed as to surround the head` of the bolt when the nut is screwed home, the head of the bolt being so formed that it cannot be screwed Iout from the nut by the application of a screw driver or like implement.

Other objects will appear in the course of the following description.

My invention is illustrated in the accompanying drawing, wherein i Figure 1 is a front elevation of the devlce in applied position; v

Figure 2 is a sectionon the line 2-2 of Figure 1;

Figure 3 is a section on the line 3-p-3 of Figure 1; Y

Figure 4 is a section on the line 4--4 of Figure 1; l"

Figures 5 and 6 are face views of the nutv and washer showing the interlocking lugs.

Referring to the dra-wing. A designates asupporting plate or rack as it may be termed and B a license plate or tag. `The elements A and B are provided with slots a and b which are adapted to be placed in coincidence with each other. The screw 10 is provided With a head 11, which head is :formed to provide what I may term a ratchet nick, that is, a nick so kformed that a screwdriver may be engaged with the nick to turn the screw in one direction, but will be automaticall ejected from the nick or revented from hol ing'upon a rotation of t e vscrewdriver in the oppositedirection. To this end, the nick 12 'is defined by diagonally .op osed shoulders 13, the u per faces of whic extend down on an inc ine Ias at 14 to the bottom' of the nick. Engageable'with the shank of the screw 10 is the nut 15 'which is interiorly screw-threaded and preferably somewhat conical and one end faceof this nut is formed with two lugs or teeth 16 which extend parallel to each other on each v'side-of the screwthreaded aperture of the nut and diametricaly with relation to the nut.

oacting with the screw and nut is a wash'- er 17 which hasa central perforation as usual to loosely receive the screw 10an'd which is providedupon one face with the two teeth or lugs 18 dis osed in diametric relation and adapted to beinserted between or interdigitate with thelugs 16 on the nut 15'.

The opposite or outside face ofthe nut is recessed at 19, the recess being of suiiicient internal diameter to'entirely receive the head 11 of the screw.

The parts described are disposed as illustrated in Figure 1, the lugs or teeth 16 of thenut 15 extending throughthe supporting plate or rack A and if necessary through the slot in plate B alsowhile the lugs o n the washer also extend through the slot b fand into engagement between the teeth or lugs 16 on the nut 15.` When the screw is turned entirely home, the head 11 will be disposed entirely within the recess 19. Under these circumstances, it is obvious that a screwdriver cannot be applied successfully to the head 11 to cause a reverse rotationof the head 11 because this screwdriver will 'be ejected as it were fromthe nick 12 by the inclined portions 14. Inasmuch as the/head 11 is disposed entirely within the recess 19, it is impossible to grip the head 11 by means of pliers, or otherwise, to cause a reverse rotation of the screw.

A rotation of the washer is rendered im'- possible by the engagement of the teeth 18 through vthe slot b of the plate B and a reverse rotation of the nut 15 is rendered impossible by the engagement of the lugs or teeth 16 with the walls ofthe slot a. If the slot bvlials a 100 width greater than the width of the teeth 18, and if the thickness of the plates A and B is such that the teeth 18 do not engage the teeth 16, then the washer mi ht be turned to rack A is of the usual thickness an a slight degree but this wou d not aiect the a sheet metal license tag, is of the usual thickness, the lug 18 will extend slightly into the space between the lugs or teeth 16.

If, however, the rack or supporting plate A be of greater thickness than usually found on small cars, the teeth 18 will not engage with the teeth 16 but, as before remarked, t e washer is incapable .of rotation because of the teeth 18 engaging the slot b. It is impossible, therefore, by using pliers and clam ing down upon the outer portion of the was er to jam it on the bolt and thus cause a rotation of the bolt because, under any circumstances, the washer is locked from rotation. If it be desired to remove the license tag or other element B, it must be cut or torn away as, for instance, by pliers and the pieces removed from between the carrier rack A and the washer. Then the washermay be m'oved forward suiciently to uncover the head end of the bolt and permit the bolt to be'reversely turned. Of course, this requires the destroying of the license tag. While I have particularly designed this bolt for use in holding license tags in place, the

license tags being of the character shown in my pending application for patent, Serial No.

. 531,814, I do not wish to be limited to this, as

obviously the bolt may be used kwith other forms of license tag or with other elements A and B within a support or carrier rack and a license tag. A

Furthermore, while I have illustrated the nut as being provided with two teeth 16 and the washer 17 as being yprovided with Vteeth or lugs disposed in line to engage between the teeth or lugs 17, it is obvious that the pair of teeth or lugs 16 may be disposed on the washer and the nut 15 provided with the teeth 17. It is suilicient that the nut and washer have interdigitating teeth on their confronting surfaces or are provided with lugs or teeth which will'it within the slots formed in the members A and B.

While I prefer to use teeth or lugs 16 and 18 which are rectangular in cross section, these lugs might be V-shaped in cross section.

1. The combination with two elements, each having a slot, of a bolt passing through the slots and having a ratchet nick inits head, a nut engaging the' bolt and a washer through which the bolt passes, the confronting faces of the washer and nut having diametrically extending projecting portions extending into the slots in the said elements to thus prevent any rotation of kthe nut or i 2. The combination with two elements, 1

each hav' a' slot, of a bolt passing through the slots an havinia ratchet nick in its head, a nut engaging e screw, and a washer through which the screw p the con'- frontmg faces of the washer and nut ha diametricall exten interdi ita It havingpa elo nu faces, e projecting throu h e slots in the elements, the outer face o the washer being receiv the head of the screw and enclose its periphery.

3. The combination with two elements each having a slot, of a bolt passingfthrough the slot and havin a ratchet nick in its head, a nut engaging e screw and a washer through whlch the screw p, the confronting faces of the washer and nut having diametrically extending parallel interdigitating teeth extendin into the slots in the elements and paralle to the longitudinal walls of the slot, the walls of said slots by. their enga ement with the teeth preventing rotation o either the nut or the washer, the outer face of the washer being to receive the head of the screw.l v h 4. The colmbinfatiolr):o 1ivith two elentsleath avingasot,o a tpassmg ou e slot and havin a ratchet nick in its hgad, a nut engaging e bolt, a washer loosely surrounding the bolt between the head and the nut, the confronting faces of the washer and nut having one a air of transversely extending teeth and e other a sin le diametricall extendin tooth adap to be receiv between e first named pair of teeth, the slot in one-of said elements having a width just suicient to receive a pair `of teeth, the outer face of the washer bein r se to receive the head of the screw an enclose its periphery.

5. The combination with two elements, each provided with a slot, of a bolt passing through the slots and having a ratchet nic in its head, a nut enaging'the bolt and a washer through whic the bolt passes and havin a recess to receive the head of the bolt, e confronting faces of the washer and nut havin diametrically extending lu adapted to lreceived within the slot of t e bracket and having a wgidth such that neither the washer nor the nut can be turned within itlhe walls of the slot when the bolt is screwed ome.

6. An attaching means of the character described comprising a bolt having a ratchet nick in its head, a nut member enga 'n the bolt, and a washer member throug w 'ch the bolt p, the face of one of these mem- -bers confronting the other member having a pair of parallel teeth extending transversely across the face of the member on each side of its central aperture, the outer faces of the teeth being spaced from the adjacent p0rtons of the perimeter of the member, the other member having a diametrcally extending tooth on its face adapted to be receved between the teeth on the rst named member.

In testimony whereof I hereunto affix my signature.

THOMAS A. KIRTON. 

